Environmentally-friendly technique of vehicles is very important technique on which survival of future motor industry is dependent. Vehicle makers are focusing on development of environmentally-friendly vehicles so as to meet environment and fuel consumption regulations.
Some examples of future vehicle technique are an electric vehicle (EV) and a hybrid electric vehicle (HEV) that use electrical energy, and double clutch transmission (DCT) that improves efficiency and convenience.
The DCT includes two clutch devices and a gear train of a manual transmission. The DCT selectively transmits torque input from an engine to two input shafts through two clutches, changes the torque selectively transmitted to the two input shafts through the gear train, and outputs the changed torque.
The DCT is used to realize a compact transmission achieving a forward speed stage higher than a fifth forward speed stage. The DCT is used as an automated manual transmission that does not require a driver's manual manipulation by controlling two clutches and synchronizing devices by a controller.
Compared with an automatic transmission with planetary gear sets, the DCT has excellent power delivery efficiency, simplifies change and addition of components for achieving multiple gear stages, and improves fuel economy.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.